Treatment of textiles with aziridine-modified polyurethanes



United States Patent 3,542,505 TREATMENT OF TEXTILES WITH AZIRIDINE.

MODIFIED POLYURETHANES Allen G. Pittman, El Cerrito, and William L.Wasley, Berkeley, Calif, assiguors to the United States of America asrepresented by the Secretary of Agriculture No Drawing. Filed Oct. 13,1967, Ser. No. 675,038 Int. Cl. D06m 13/48 U.S. Cl. 8127.6 '14 ClaimsABSTRACT OF THE DISCLOSURE Polyurethanes containing isocyanate groupsare reacted with alkylene imines to prepare aziridine-modifiedpolyurethanes useful for application to textile materials to improvetheir properties, e.g., to impart shrink resistance and durable pressqualities. Typical example: A polyether polyurethane containing free NCOgroups is reacted with ethylene imine to yield an aziridine-modifiedpolymer which is formed into an emulsion and applied to a textilematerial. The treated textile may be directly cured or the curingoperation may be delayed until the fabric is manufactured into afinished garment, the latter system being preferred to attain permanentcreases.

A non-exclusive, irrevocable, royalty-free license in the inventionherein described, throughout the world for all purposes of the UnitedStates Government, with the power to grant sublicenses for suchpurposes, is hereby granted to the Government of the United States ofAmerica.

This invention relates to and has among its objects the provision ofnovel processes for treating textile materials and the products of suchprocesses. A special object of the invention is the provision of suchtreatments involving the use of aziridine-modified polyurethanes wherebyto provide such benefits as improved shrinkage resistance and permanentpress qualities. Further objects and advantages of the invention will beevident from the following description wherein parts and percentages areby weight unless. otherwise specified.

The prior artadiscloses that various aziridine derivatives havebeenQproposed for use as shrinkproofing agents for W001. See Tesoro,U.S. Pats. 3,165,375 and 3,279,882, and Textile Research Journal, June1964, pp. 523-532. Among the aziridines tested by said investigator werecertain so-called amino-aziridines (those in which the nitrogen atom ofthe aziridine rings is an amino nitrogen) and amido-aziridines (those inwhich the nitrogen atom of the aziridine rings is an amido nitrogen). Itis reported by this investigator that eifectiveness of the aziridines asshrinkproofing agents is related to the basicity of the ring nitrogens,so that the aminoaziridines provide good shrinkproofing results whilethe amido aziridines do not. In fact, Pat. 3,179,882 discloses thatetfective shrinkproofing results are obtained with the amio aziridinesonly when they are applied conjointly with a polyamine (i.e., a basiccompound). Further advantages attributed to the amido aziridines by thesaid investigator are that they stiffen the treated fabric and causesevere losses in abrasion resistance (Text. Res. Jour., June 1964, p.529).

We have found that a novel class of aziridine derivatives exhibits anunusual ability to improve the properties of textiles, particularlywool. Our agents are not only chemically distinct from those of theprior art, but also obviate the problems analyzed above. Some of thesignificant advantages provided by our aziridine deriva tives are listedbelow:

They provide elfective shrinkproofing even when applied in smallproportions to the textile material.

They are effective per se; the conjoint application of a polyamine isunnecessary. It may be noted in this connection that application ofpolyamines to wool is hazardous because if any unreacted polyamineremains on the wool it will cause yellowing and degradation of thefibers.

They do not adversely aifect the abrasion resistance of the textilematerial. In fact, the treated material often exhibits increasedabrasion resistance. In contrast, the amido aziridines studied by Tesoroare admitted to cause decrease in abrasion resistance.

They do not cause a stiffening of the fabric. This is in sharp contrastto Tesoros findings that effective shrinkproofing is coupled withstilfening; indeed, that the degree of stiffening is proportional toshrinkproofing efficiency. See Text. Res. Jour., June 1964, p. 529.

They do not affect the intrinsic properties of the fibers, such ascolor, tensile strength, flexibility, hand, porosity, etc. so that thetreated fibrous materials can be em ployed in any of the usual textileapplications as in fabricating shirts, skirts, trousers, and othergarments.

They provide flat-setting and durable crease qualities.

The aziridines of the invention are particularly useful in applicationsinvolving delayed curing, that is, where the aziridine is applied to thefabric, the treated fabric is manufactured into a garment provided withappropriate creases in selected areas, and the garment is then subjectedto a curing treatment so that the completed garment is not only shrinkresistant but also press-free, i.e., it can be subjected to repeatedwashings without requiring pressing to maintain the creases. Theparticular ad vantages of the present invention which make themespecially adapted to such use are: Our aziridines do not undergospontaneous curing; they remain in the uncured state even after longstorage of the treated fabric. The aziridines remain in the uncuredstate even if subjected to moisture at ordinary temperatures. Thus, thetreated fabrics may be subjected to moist conditions as may be requiredin certain garment fabrication steps without premature curing andwithout decomposition of the applied aziridine.

The aziridines of theinvention may aptly be described asaziridine-modified polyurethanes, and have the structure:

I u 9 0 NHR-NH-d- I L I R, arm" n wherein:

A is the residue of a polyether polyol or polyester polyol having avalence of n,

R is a hydrocarbon radical containing at least two can bon atoms,

R is hydrogen, halogen, lower alkoxy, or a radical of the structure R"is hydrogen or a lower alkyl radical, n is an integer from 2 to 10, andx is an integer from 1 to 2..

The aziridine derivatives of the invention are prepared by reacting analkylene imine, such as ethylene, propylene, or butylene imine, with apolyether (or polyester) polyurethane containing free isocyanate groups.This simple reaction establishes the desired aziridine-modfiication forpadding and insulation applications, and in the proof the startingpolymer. A typical, but by no means least two free NCO groups perpolymer molecule. Prelimiting, example of the synthesis is illustratedbelow: ferred are the polymer intermediates having a molecular ([JH;(EH3 f H Isoeyanate-terminated ooN NH-iI-OTCHzCHzCHzOH2O7CNH NCO WyethWlyurethane 2CH2-CH2 Ethylene imine ([3113 (3H3 CE; H (l) /CH2 l N- NHNH( 1-O CH2CHzCHa- CHrO}-CNH NHC-N C a m Hz Azlrldine-modified polyetherpolyurethane (In the above formulas, m represents the number of Weightof at least 500, more preferably those having a tetramethyleneetherrepeating units. This may range, for 25 molecular weight of at least1000. Also, it is generally example, about from 5 to 50.) preferred touse the polyether-based polymers, for ex- The reaction is carried out atabout to 40 C., ample,-the NCO-containing polyurethane derived from andunder essentially anhydrous conditions to avoid hypolyalkylene etherglycols such as polyethylene ether drolysis of the isocyanate groups.The alkylene imine glycols,-polytrimethylene ether glycols,polytetramethylene is supplied in excess to ensure conversion of allisocyanate ether glycols, polypropyleneether glycols and the like.

groups to aziridine groups. It is evident from the for- THE POLYMERINTERMEDIATES mulas above that modification in the aziridine rings canbe effected by selection of the alkylene imine reactant. Polyether p ypolyurethanes containing free For example, if propylene imine i d i t df h l. isocyanate groups useful as intermediates for the present eneimine, the aziridine rings will be of the structure invention y bfi P pas Well known in the aft, y reacting a polyether (or polyester) polyolwith a 2 polytsocyanate, using an excess of the latter to ensureprovision of free isocyanate groups in the product. A cH, typical, butby no means limiting, example is illustrated H below:

HO CHzCHzCHPCHz-O Polyether polyol 2 N C O Polylsocyanate NCO (IJHa(3113 (R f fi Isocynate-terminated ooN NH-d-o om-om-om-oHt-o c-NH NCOPmymthm In other words, in this case R" (in Formula I) is 0 (In theabove formulas m represents the number of methyl. tetramethyleneetherrepeating units. This may range, for

Referring to Formula I, above, it is evident that selecexample, aboutfrom 5 to 50.) tion of the polymer intermediatethe polyether or poly-Representative examples of polyisocyanates which may ester polyurethanecontaining free isocyanate groups be employed for reaction with thepolyether (or polywill determine the values of A, R, R, n, and x. Theprepester) polyol include: aration of these intermediates is well knownin the art;

they are widely used in the production of urethane foamstoluenenzA-dnsocyanate toluene-2,6-diisocyanate commercial mixtures oftoluene-2,4 and 2,6-diisocyanates ethylene diisocyanate ethylidenediisocyanate propylene-1,2 diisocyanate duction of elastomers. Althoughthe preparation of these intermediates forms no part of the presentinvention, this subject will be explained below to illustrate the widerange of intermediates Which may be employed l h x lene-1,2-diisoeyanatein producing the aziridine derivatives of the invention.cyclohexylene-1,4-diis0cyanate Thus, for the purposes of the invention,the intermediate m-phenylene diisocyanate may be any polyetherpolyurethane which contains at 3,3'-diphenyl-4,4-biphenylenediisocyanate 4,4-biphenylene diisocyanate 3,3'-dichloro-4,4-biphenylenediisocyanate 1,6-hexamethylenediisocyanate1,4-tetramethylene-diisocyanate l,10-decamethylenediisocyanate1,S-naphthalenediisocyanate cumene-2,4-diisocyanate 4-methoxyl ,3-phenylenediisocyanate 4-chloro-1,3-phenylenediisocyanate4-bromo-l,3-phenylenediisocyanate 4-ethoxy-l,3-phenylenediisocyanate2!,4-diisocyanatodiphenylether 5,6-dimethyl-l,3-phenylenediisocyanate2,4-dirnethyl-l,3-phenylenediisocyanate 4,4'-diisocyanatodiphenyletherbenzidinediisocyanate 4,6-dimethyl-l,3-phenylenediisocyanate9,10-anthracenediisocyanate 4,4-diisocyanatodibenzyl3,3-dimethyl-4,4'-diisocyanatodiphenylmethane2,6-dimethyl-4,4-diisocyanatodiphenyl 2,4-diisocyanatostilbene3,3-dimethyl-4,4'-diisocyanatodiphenyl3,3'-dimethoxy-4,4'-diisocyanatodiphenyl 1,4-anthracenediisocyanate2,5-fluorenediisocyanate 1,8-naphthalenediisocyanate2,6-diisocyanatobenzfuran 2,4,6toluenetriisocyanate, andp,p',p"-triphenylmethane triisocyanate.

It is evident that the selection of the polyisocyanate reactant willdetermine the values of R and R in Formula I. For example, where thereactant is a hydrocarbon diisocyanate, R will be a hydrocarbon radicaland R will represent a hydrogen atom forming part of said hydrocarbonradical. Where the reactant contains a substituent such as chlorine ormethoxy-as would be the case with, for example, 4-chloro-l,3-phenylenediisocyanate or 4- methoxy-l,3-phenylene diisocyanate-R will be thehydrocarbon residue of the reactant and R will be thesubstituentchlorine or methoxy in the given examples.

The polymer intermediates useful for the purposes of the invention may,in turn, be derived from any of a wide variety of polyether polyols andpolyester polyols, and representative examples of these polyols aredescribed below:

Among the polyether polyols which may be so used are those prepared byreaction of an alkylene oxide with an initiator containing activehydrogen groups, a typical example of the initiator being a polyhydricalcohol such as ethylene glycol. The reaction is usually carried out inthe presence of either an acidic or basic catalyst. Examples of alkyleneoxides which may be employed in the synthesis include ethylene oxide,propylene oxide, any of the isomeric butylene oxides, and mixtures oftwo or more diiferent alkylene oxides such as mixtures of ethylene andpropylene oxides. The resulting polymers contain a polyether backboneand are terminated by hydroxyl groups. The number of hydroxyl groups perpolymer molecule is determined by the functionality of the activehydrogen initiator. For example, a difunctional alcohol such as ethyleneglycol (as the active hydrogen initiator) leads to polyether chains inwhich there are two hydroxyl groups per polymer molecule. Whenpolymerization of the oxide is carried out in the presence of glycerol,a trifunctional alcohol, the resulting polyether molecules contain anaverage of three hydroxyl groups per molecule. Even higherfunctionalitymore hydroxyl groupsis obtained when the oxide ispolymerized in the presence of such polyols as pentaerythritol,sorbitol, dipentaerythritol, and the like. In addition to those listedabove, other examples of polyhydric alcohols which may be reacted withalkylene oxides to produce useful polyether polyols include:

propylene glycol trimethylene glycol 1,2-butylene glycol 1,3-butanediol1,4-butanediol 1,5-pentanediol 1,2-hexylene glycol 1, l0-decanediol1,2-cyclohexanediol 2-butene-1,4diol 3-cyclohexene-1,l-dimethanol4-methyl-3-cyclohexene-1,l-dimethanol B-methylene-1,5-pentanedioldiethylene glycol (Z-hydroxyethoxy -1-propanol 4- (Z-hydroxyethoxy)-1-butanol 5- Z-hydroxypropoxy) l-pentanol 1- (2-hydr0xymethoxy)-2-hexanol I-(Z-hydroxypropoxy)-2-octanol 3-a1lyloxy-1,5-pentanedio12-allyloxymethyl-Z-methyl-1,3-propanediol (4-pentyloxy) methyl] 1,3-propanediol 3-(o-propenylphenoxy) 1,2-propanediol thiodiglycol 2,2-[thiobis (ethyleneoxy) diethanol polyethyleneether glycol (molecularweight about 200) 2,2-isopropylidenebis (p-phenyleneoxy) diethanol1,2,6-hexanetriol l,l,l-trimethylolpropane 3- (2-hydroxyethoxy)-1,2-propanediol 3-(Z-hydroxypropoxy)-1,2-propanediol 2,4-dimethyl-2-(Z-hydroxyethoxy) methylpentanediol-1,5

1,1, l-tris[ (Z-hydroxyethoxy) methyl] ethane 1,1,1-tris(Z-hydroxypropoxy methyl] propane triethanolamine triisopropanolamineresorcinol pyrogallol phloroglucinol hydroq-uinone 4,6-di-tertiarybutylcatechol catechol orcinol methylphloroglucinol hexylresorcinol3-hydroxy-2-naphthol 2-hydroxy-l-naphthol 2,5-dihydroxy-l-naphtholbis-phenols such as 2,2-bis-(p-hydroxyphenyl)propane andbis-(p-hydroxyphenyl) methane 1, 1,2-tris- (hydroxyphenyl) ethane1,1,3-tris-(hydroxyphenyDpropane.

An especially useful category oi polyether polyols are thepolytetramethylene glycols. They are prepared by the ring-openingpolymerization of tetrahydrofuran, and contain the repeating unit.

in the polymer backbone. Termination of the polymer chains is byhydroxyl groups.

The polyester polyols which may be employed as precursors for theaziridines of the invention, are most readily prepared by condensationpolymerization of a polyol with a polybasic acid. The polyol and acidreactants are used in such proportion that essentially all the acidgroups are esterified and the resulting chain of ester units isterminated by hydroxyl groups. Representative examples of polybasicacids for producing these polymers are oxalic acid, malonic acid,succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid,azelaic acid, sebacic acid, brassylic acid, thapsic acid, maleic acid,fumaric acid, glutaconic acid, a-hydromuconic acid, fi-hydromuconicacid, a-butyl-u-ethylglutaric acid, a,p-diethylsuccinic acid, 0-phthalic acid, isophthalic acid, terephthalic acid, hemimellitic acid,trimellitic acid, trimesic acid, mellophanicacid, prehnitic acid,pyromellitic acid, citric acid, benzenepentacarboxylc acid,l,4-cyclohexanedicarboxylic acid, diglycollic acid, thiodiglycollicacid, dimerized oleic acid, dimerized linoleic acid, and the like.Representative examples of polyols for forming these polymers includesethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol,1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol,butene-l,4-diol, 1,5-pentane diol, 1,4-pentane diol, 1,3-pentane diol,1,6-hexane diol, hexene-1,6-diol, 1,7-heptane diol, diethylene glycol,glycerine, trimethylol propane, 1,3,6-hexanetriol, triethanolamine,pentaerythrtiol, sorbitol, and any of the other polyols listedhereinabove in connection with the preparation of polyether polyols.

An interesting class of polyester polyols are those which includepolyether units so that they may be considered as polyester polyols oras polyether polyols, depending on whether the ester or the ether groupsare in majority. The compounds may be produced by the condensationpolymerization of any of the above-mentioned polybasic carboxylic acidswith a polyalkyleneether glycoltypically, a polyethyleneether glycolhaving a molecular weight of about 200 to 2000-using the glycol in therequire proportion to assure termination by hydroxyl.

Esters of the hydroxyl-co'ntaining acid, ricinoleic acid, form anothercategory of useful polyester polyols. Typically, one can use esters ofricinoleic acid with ethylene glycol, propylene glycol, glycerol,pentaerythritol, diglycerol, dipentaerythritol, polyalkyleneetherglycols, and the like. Representative of this category of polyesterpolyols is castor oil which is composed mainly of the tri-glyceride ofricinoleic acid.

APPLICATION OF THE AZIRIDINE TO THE TEXTILE The aziridines of theinvention may be applied to the textile in various ways. One techniqueinvolves applying the aziridine as such to the textile, using warming ifnecessary to make the aziridine flow, and distributing it with calenderrolls or the like. A preferred technique involves dissolving theaziridine in an inert, volatile solvent and applying the resultingsolution to the textile material. Typical of the solvents which may beused are benzene, toluene, xylene, dioxane, diisopropyl ether, dibutylether, butyl acetate, chlorinated hydrocarbons such as chloroform,carbon tetrachloride, ethylene dichloride, trichloroethylene,1,3-dichlorobenzene, fiuorohydrocarbons such as benzotrifiuoride, 1,3bis-(trifiuoromethyl)benzene, etc., petroleum distillates such aspetroleum naphthas, etc. Usually it is preferred to use the aziridinesin the form of aqueous emulsions. These can be prepared by customarytechniquesagitation of the aziridine with water and a conventionalemusifying agent such as an alkylphenoxypoly-(ethyleneoxy)ethanol,polyoxyethylene sorbitan monopalmitate, polyoxyethylene lauryl ether,polyoxyethylene-polyoxypropylene stearate, sorbitan monopalmitate, I

sorbitan monolaurate, and the like. The concentration of the aziridinein the dispersionthis last term being herein employed in a generic senseto include solutions and emulsins-is not critical and may be varieddepending on such circumstances as the solubility characteristics ofaziridine, the amount of aziridine to be deposited on the fibers, theviscosity of the dispersion, etc. In general, a practical range ofconcentration would be from about 1% to about The dispersion may bedistributed on the textile material by any of the usual methods, forexample, by spraying, brushing, padding, dipping, etc. A preferredtechnique involves immersing the textile in the dispersion and thenpassing it through squeeze rolls to remove the excess of liquid. Suchtechniques as blowing air through the treated textile may be employed toreduce the amount of liquid which exists in interstices between fibrouselements. In any case, the conditions of application are so adjustedthat the textile material contains the proportion of aziridine desired.Generally, the amount of aziridine is about from 0.5 to 20%, based onthe weight of the textile ma- 8 terial but it is obvious that higherproportions may be used for special purposes. In treating textiles suchas fabrics the amount of aziridine is usually limited to a range ofabout 0.5 to 10% to attain the desired end such as shrink resistancewithout interference with the hand of the textile.

After application of the aziridine, the treated textile is cured(heated) to effect an insolubilization ofthe applled aziridine and topromote bonding of the azirine to the textile. Although the mechanism ofbonding has not been identified, bonding is known to occur and it isbelieved to involve chemical combination of the aziridlne w th activeradicals present in the textile substrate, these act ve radicalsincluding carboxyl, hydroxyl, amino, and th ol groups. Such groups are,of course, present in many textile materials including wool, animalhair, leather, and other proteinaceous materials; cotton, rayon, linen,and other cellulosic fibers, nylon, polyurethanes, and many othersyntheic fibers.

In cases where the aziridine is applied as a dlspersion, that is, asolution, emulsion, or suspension, the solvent or other volatiledispersing medium is preferably evaporated prior to the curingoperation. Such prior evaporation is not a critical step and theevaporation may be simply effected as part of the curing step. Thetemperature applied in the curing step is not critical and usually iswithin the range from about 50 C. to about 150 It is obvious that thetime required for the curing will vary with such factors as thereactivity of the selected aziridine, the type of textile material, andparticularly the temperature so that a lower curing temperature Wllirequire a longer curing time and vice versa. It will be further obviousto those skilled in the art that in any particular case the temperatureof curing should not be so high as to cause degradation of the textileor the azlridme. In many cases an adequate cure is elTected by heatlngthe treated textile in an oven at about C. for about 5 to 60 minutes.

Although the present invention is of particular advantage in itsapplication to wool, this is by no means the only type of fiber whichcomes into the ambit of the invention. Generically, the invention isapplicable to the treatment of any textile material and this materialmay be in any physical form, e.g., bulk fibers, filaments, yarns,threads, slivers, roving, top, webbing, cord, tapes, woven or knittedfabrics, felts or other non-woven fabrics, garments or garment parts.Illustrative examples of textile materials to which the invention may beapplied are: Polysaccharide-containing textiles, for instance, thoseformed of or containing cellulose or regenerated celluloses, e.g.,cotton, linen, hemp, jute, ramie, sisal, cellulose acetate rayons,cellulose acetate-butyrate rayons, saponified acetate rayons, viscoserayons, cuprammonium rayons, ethyl cellulose, fibers prepared fromamylose, algins, or pectins; mixtures of two or more of suchpolysaccharide-containing textiles. Protein-containing textiles, forinstance, those formed of or containing wool, silk, animal hair, mohair,leather, fur, regenerated protein fibers such as those prepared fromcasein, soybeans, peanut protein, zein, gluten, egg albumin, collagen,or keratins, such as feathers, animal hoof or horn. Mixtures of any twoof more protein-containing textiles. Mixtures ofpolysaccharide-containing textiles and protein-containing textiles,e.g., blends of wool and cotton; wool and viscose, etc. Textiles formedof or containing synthetic resins, e.g., alkyd resins, polyvinylalcohol, partially esterified or partially etheri-fied polyvinylalcohol, nylon, polyurethanes, polyethylene glycol terephthalate,polyacrylonitrile, polyethylene, polypropylene, polyvinyl chloride, andpolyvinylidene iodine chloride. Blends of natural fibers such as cottonor Wool with synthetic fibers such as nylon, polyethyleneglycolterephthalate, acrylonitrile, etc. Inorganic fibers such as asbestos andglass fibers. The applications of the teachings of the invention may befor the purposes of obtaining functional or decorative effects such asshrinkproofing, developing permanent crease qualities, sizing,finishing, increasing abrasion resistance, increasing gloss ortransparency, increasing water-, oil-, and soil-repellency, increasingadhesion or bonding characteristics of the substrates with rubber,polyetser resins, etc.

DELAYED CURE SYSTEM A particular embodiment of this invention isconcerned with the production of wool products which exhibit not onlyshrink resistance but also permanent press qualities. Heretofore, no onehas been able to impart this combination of useful properties to wool.Existing wool shrinkproofing treatments do lead to dimensionally-stablefabrics; however, when the fabrics are washed or drycleaned they have amussy appearance and must be pressed. Creases have been set in woolengarments by, for example, treatment with reducing agents such asammonium thioglycollate or sodium bisulphite. The creases, however, donot withstand aqueous laundering nor generally more than 1 or 2dry-cleanings. Of course, no shrinkproofing is attained with thesecreasing procedures. Attempts to combine wool shrinkage treatments withcreasing treatments have not been successful in that although shrinkagecan be controlled, creases are lost after aqueous laundering and thefabrics need ironing for neat appearance. Various materials such asmelamine-formaldehyde resins, urea-formaldehyde resins,dihydroxy-ethylene dimethylol urea, or alkyl carbamates, which arecommercially used in producing permanently creased garments of cotton orcotton-synthetic blends have proved entirely unsuccessful when appliedto wool.

However, these problems are obviated by the present invention. Byapplication of our aziridines to wool fabrics one attains resistance toshrinkage, a smooth wrinkle-free appearance after washing ordry-cleaning so that no ironing is required, and creases and pleatsimparted to the fabric are permanent-they withstand repeated aqueouslaundering or non-aqueous dry-cleaning.

This embodiment of the invention is most profitably practiced in asystem which incorporates a delayed cure, that is, the aziridine isapplied to the fabric but curing is delayed until the fabric has beenmade up into the desired product which may be, for example, a completedgarment. The curing then not only bonds the aziridine to the fabric, butalso renders permanent the creases or pleats which have been imparted tothe fabric. Typical ways of practicing this embodiment of the inventionare described in detail below:

The aziridine is applied to the fabric using a solution or emulsion ofthe aziridine, as described hereinabove. The conditions of applicationmay be adjusted to vary the amount of aziridine deposited on the fabric.Usually, it is preferred to deposit about 0.2 to 20% of the aziridine,based on the weight of the fabric. In a preferred modification of theprocedure a reducing agent, such as sodium bisulphite, is incorporatedin the liquid preparation of the aziridine. However, as hereinafterexplained the reducing agent may be applied at a later stage in theprocess. The treated fabric is then dried to remove the solvent or othercarrier in which the aziridine was dispersed for the application step.The drying may be in air at ordinary (room) temperature, or, warm airmay be applied to increase the rate of evaporation. To avoid prematurecuring, the temperature of the treated fabric should be kept below about50 C. However, since curing does not occur immediately, short exposuresto higher temperatures are permissible.

The fabric containing the aziridine in its uncured state is then made upinto the desired product. This may be, for example, a garment, in whichcase the fabric would be subjected to the usual garment-makingoperations of cutting, sewing, and pressing. Included in theseoperations would be formation of creases or pleats in selected areas bythe usual pressing methods employed by the tailor. In the event that areducing agent was not coapplied with theaziridine, then a reducingagent may be applied to the textile during the moistening step whichcommonly forms a part of the pressing operation. For example, an aqueoussolution of the reducing agent may be sprayed on the textile,particularly in those areas where it is intended to form creases orpleats. Enough of the solution is usually applied so there is about 0.1to 2% of the reducing agent, based on the weight of fabric. It is to beparticularly emphasized that the production of garments need not followdirectly after the aziridine treatment of the fabric. Indeed, the fabriccontaining the uncured aziridine can be held for long periods withoutdanger of spontaneous curing. The aziridines of the invention areparticularly characterized by their stability, i.e. their ability toremain in an uncured state for long periods of time. Moreover, theirstability is not affected by moisture. If moisture is applied (asnecessary in certain garment fabricating steps) there is no danger ofpremature curing.

The garment or other textile article is then subjected to a curingoperation to insolubilize the aziridine and bond it to the wool fibers.Typically, the curing is accomplished by placing the garments in an ovenwhere they are maintained at a temperature and for a time sufiicient tocause the desired curing of the applied aziridine. In general,temperatures of at least 50 C., preferably about -150 C., are appliedfor period of about 5-60 minutes. The product after removal from theoven is now ready for use or for sale and, as previously noted, exhibitsnot only resistance to shrinkage when washed but also retains itspleats, creases, or other conformations imparted to the garment. Also,when washed, the products retain a neat appearance free from wrinklingor mussiness so that they are truly press-free, i.e., no pressing isneeded even after repeated washings.

As noted hereinabove, where permanent crease qualities are desired, areducing agent is preferably applied to the textile, concomitantly withapplication of the aziridine or in a later step but prior to curing.Representative examples of reducing agents include: Inorganic sulphidessuch as alkali metal, alkaline earth metal, ammonuim, etc. sulphides andhydrosulphides. Organic compounds containing a thiol group, as, forexample, thioglycollic acid, or its salts such as the alkali metal orammonium salts; beta-mercapto ethanol; monthio glycerol;dithio-glycerol; butyl mercaptan; thiomalic acid or its salts;thio-lactic acid or its salts; thiophenol; thiocresol; etc. Formamidinesulphinic acid, also known as iminoaminomethane sulphinic acid betaine.Formaldehyde sulphoxylates, generally used in the form of their alkalimetalwzinc, or ammonium salts. Alkali metal or ammonium sulphites,bisulphites and hydrosulphites. Aldehyde or ketone adddition productswith sulphites or bisulphites, e.g., sodium formaldehyde bisulphite,sodium acetone bisulphite, etc. Generically, the reducing agents used inaccordance with the invention may be defined as sulphur-containing,reductive, disulphide-splitting agents because of the fact that they allcontain sulphur in their structures and because they have the ability toopen the disulphide (cysine) linkage in the wool molecule, generallyconverting a single disulphide (--SS) bond into two thiol (-SH) groups.

The amount of reducing agent is not critical and may be varied dependingon such circumstances as the eflicacy of the agent selected, thedurability of set desired in the product, the character of the fibersbeing treated, etc. Even minute amounts of the reducing agent willprovide some degree of improvement. Usually, the reducing agent is usedin an amount from about (1L1 to about 2%, based on the weight of thetextile substrate being treated. It is, of course, obvious that thereducing agent should not be applied in such a high proporion as woulddegrade the textile substrate.

Although the use of a reducing agent in conjunction with our aziridinesis primarily of advantage in treat- 1 1 ments where the substrate is tobe provided with durable creases or other configurations, it is withinthe broad ambit to employ the reducing agent in other procedures, e.g.,ones wherein creasing is not involved. The advantage of the reducingagent is that it enhances bonding of the aziridine to the textilesubstrate. Thus, generically, the invention includes in is broad compassany textile-treating procedure wherein the reducing agent is used inconjuncton with our aziridines, and is appled to the textileconcomitantly with the aziridine or at any earlier or later stage, priorot the curing step.

EXAMPLES The invention is further demonstrated by the followingillustrative examples.

Washing procedure for shrinkage tests: The samples were washed in areversing agitator-type household washing machine, using a three-poundload, a water temperature of 105 F, and a low-sudsing detergent in aconcentration of 0.1% in the wash liquor. The wash cycle itself was for75 minutes, followed by the usual rinses and spin-drying. The dampmaterial from the washer was then tumble-dried in a household-typeclothes dryer. The dried samples were measured to determine their lengthnad width and the shrinkage calculated from the original dimensions.

Example 1.Preparation of aziridine-modified polytetramethyleneetherpolyurethane (fHs (EH:

This indicated preparation of the desired aziridine derivative.

(B) To a IOO-gram sample of the aziridine solution, prepared asdescribed above, was added 4 grams of a commercial oil-solubleemulsifying agent, an alkylphenoxypoly(ethyleneoxy)ethanol. The mixturewas stirred rapidly and cc. of water were slowly added. The thickwaterin-oil emulsion was transferred to a blender and an additional 200cc. of water was added while stirring at high speed. The resultingoil-in-water emulsion of the aziridine was used as a stock supply anddiluted with water as needed.

Example 2.---Application of aziridine-modified polytetramethyleneetherpolyurethane The emulsion prepared as described above in Example 1 wasdiluted with water (to levels indicated below) and applied to swatchesof wool. In some instances, measured amounts of NaHSO were added to theemulsions.

The treatments in each case were as follows: Wool swatches were immersedin the emulsion bath until completely wet-out, then the swatches wererun through a squeeze roll to attain a wet-pick-up of 80100%, based onthe weight of the fabric. The damp fabrics were dried in air at roomtemperature.

Next, the dried fabrics were creased: Each swatch was moistened byspraying with water, folded, and then subjected to steaming and pressingon a tailors hot-head press. The fabrics were steamed for 10-20 seconds,then pressure (-80 p.s.i.) and heat (ca. 140l50 C.) applied for 20seconds. The creased swatches were then cured in a forced draft oven at300 F. for 20 minutes.

The cured swatches were then given three 75-minute washes (as describedabove) and tumble-dried after each wash. The swatches were measured forshrinkage and examined for crease retention and over-all appearanceafter each tumble drying (following each wash).

In a first series of runs, applied to an undyed woolen fabric, thefollowing results were obtained:

TABLE I 1st washing and drying 2nd washing and drying 3rd washing anddrying Area Area Area Cone. of aziridine in treating shrinkage,shrinkage, shrinkage, emulsion, percent percent Appearance percentAppearance percent Appearance 4 0.8 E 0. 5 E 0.5 E 3 2. 1 G 1. 6 F 2. 4P 2 2. 0 G 1. 5 F 2. 0 P 2 (plus 1% NaHSOa). 2. 3 E 2.0 E 2. 7 E None(untreated wool 18. 1 48. 3

*Fabric appearance was rated as follows:

Excellent (E) =sharp crease, fabric flat and in no need of ironing. Good(G) =sharp crease, fabric fiat but could use slight touching up with theiron. Fair (F) =crease still visible but not sharp, some wrinkling,needs definite ironing;

Poor (P) =no crease visible, badly wrinkled.

wherein A represents the residue of a polytetramethyleneether glycolcontaining about twenty-five units.

(A) Two hundred grams (0.1 mole) of the poly- 1st washing and drying 2ndwashing and drying 3rd washing and drying Area Area Area Cone. ofaziridine in treating shrinkage, shrinkage, shrinkage, emulsion, percentpercent Appearance percent Appearance percent Appearance 4 2.8 E 1. E 2.2 G 3 3. 2 E 3. 2 G 5. 2 F 2 (plus 3% NaHSOa)--- 3. 5 E 2. 0 E 3.0 ENone (untreated wool) 46. 6 59. 7

*Fabrie appearance was rated as described in Table I:

Example 3.Examination of treated fabrics at intervals for delayed-curefeatures The emulsion prepared as described in Example 1 was diluted toan aziridine concentration of 2%. In one of the runs,the dilutedemulsion per se was used; in a second run spectrum of the solutionrevealed no residual NCO groups. 2% of NaHSO was added.

Wool fabric was treated as follows: Swatches of the wool were wet-out inthe emulsion bath, pressed to 80- 100% wet pick-u and air-dried at roomtemperature. The dried fabrics were then stored at room temperature, andafter certain times of storage (3, 8, 1.5, and 30 days) were creased andcured as described in Example 2. The swatches were then subjected tofour 75-minute washes with tumble-drying after each wash. The resultsare tabulated below:

TABLE III Properties, aiter 4th washing Time of storage before settingBisulphlte in Area and curing, emulsion shrinkage, days bath percentAppearanee 2.1 E 2.1 G 2.2 E 2.0 G 1.8 E 2.0 G 2.2 E 2.3 E 4 28. 3

1 Appearance was rated as described in Table I. 1 In this run, there-moistening of the fabric (part of the creasingoperagimfiwsagaecomplished by spraying with an aqueous solutioncontaining a s. g Untreated wool. After 2 washes.

OCN

Example 4 The starting material for this synthesis was a com* mercialliquid polyether polyurethane having a molecular weight of about 850 andan isocyanate (-NCO) content of about 9.5%. It is believed to have thestructure wherein A represents the residue of polytetramethyleneetherglycol containing about seven One hundred grams (0.12 mole) of theliquid poly urethane was dissolved in 300 ml. of dry benzene. Whilestirring, 13 ml. (0.26 mole) of ethylene imine was added at a rate slowenough that the reaction temperature did not rise above 40 C.

An emulsion containing 3% of the aziridine-modified polyurethane wasprepared as follows: To 47 grams of the solution of the aziridinepolymer, prepared as described above, was added 1 gram of a commercialemulsifier, tris(polyoxyethylene)sorbitan monopalmitate, and 450 ml. ofwater and applying rapid agitation in a blender. More dilute emulsionswere prepared by incorporating water in this stock emulsion.

Samples of wool flannel were treated with the emulsions by padding withthe emulsion, squeezing through rollers to remove excess liquid, andthen curing in an oven for 20 minutes at 300 F.

The treated samples were then tested for shrink resist ance, using theAccelerotor method. In this test the fabric samples are milled at 1700r.p.m. for 2 minutes at 40-42 C. in an Accelerotor with aqueous sodiumoleate (0.5%) solution, using a liquor-to-Wool ratio of 50 to 1. Afterthis washing operation, the samples were measured to determine theirarea and the shrinkage calculated from the original area. This is a verysevere test which applied to untreated wool samples gives an areashrinkage of 40-50%. The Accelerotor is described in American DyestuflReporter, vol. 45, p. 685, Sept. 10, 1956.

The results obtained are tabulated below.

The starting material for the synthesis was a commercial liquidpolyether polyurethane having a molecular weight of about 1300 and anisocyanate (NCO) content of 6.5%. It is believed to have the structure OLNH NCO ea. 13

One hundred grams (0.077 mole) of the liquid poly urethane was dissolvedin 200 grams of dry benzene. To this solution was added 7 grams (0.16mole) of ethylene imine at a rate slow enough so that the temperature ofthe reaction mixture did not rise about 35 C. Five minutes after thelast of the ethylene imine had been added, the LR. spectrum of thereaction mixture showed that no free NCO was present.

Emulsions were prepared of the aziridine-modified polyurethane, andthese were applied to wool flannel, and tested for shrinkage, all asdescribed above in Example 4. The results are tabulated below.

Concentration of aziridine- Area shrinkage modified polyurethane in(Accelerotor test) emulsion, percent: percent 3 None (control) 42Example 6 CH-CH:

Fifty grams of the aziridine-modified polymer-having a molecular weightof 6300-6800 and containing 0.36 to 0.38 milliequivalents of imine pergram of polymer-was dissolved in 50 grams of benzene and '2 grams of acommercial emulsifier, a polyoxyethylene-polyoxypropylene 15monostearate, was added. While stirring the solution in a blender, waterwas gradually added to make 1000 grams of an emulsion.

this the samples were measured for shrinkage and assayed for retentionof creases and general appearance. The results obtained are tabulatedbelow:

Properties after three 75-min. washes *Appearanco was rated as describedin Table I.

A sample of wool flannel was immersed in the emulsion for 1 minute, thenpassed through squeeze rollers, 1

and then dried in air. From the increase in weight of the fabric theuptake of polymer was found to be 4%. The treated fabric was cured (300F., 10 minutes), then tested for shrinkage by the Accelerotor methoddescribed above. Area shrinkage was found to be 1%. A Sample of the samefabric but untreated shrank 39.7% in area by the same test.

Example 7 A series of experiments were carried out to compare theeffectiveness of the aziridine derivatives of the invention with that ofvarious commercial products recommended for shrinkproofing applications.The various products tested were:

(A) The aziridine-modified polyalkyleneether polyurethane describedabove in Example 1. It was applied in the form of 2% emulsion to whichhad been added sodium bisulphite (1% (B) A polyamide modified byreaction with epichlorhydrin. This material is commercially available asa water-soluble resin (Kymene manufactured by Hercules Co.) and containsepoxide linkages available for reaction with wool and for cross-linking.This product was applied in form of a 2.5% solution in water, afid towhich was added sodium bisulphite (1% (C) A polyacrylate containingmethylol groups (CH OH) which can cross-link and/or react with hydroxygroups in wool by elimination of water. The main component of thepolymer is a soft acrylate, polybutyl acrylate. It is sold under thename HA-8 by Rohm and Haas Co. for wool shrinkproofing and other uses.It was used with an acid catalyst, ZnNO in accordance with themanufacturers recommendation. It was applied in the form of a 4%emulsion, to which was added sodium bisulphite (1% (D) Aurea-formaldehyde condensation product, consisting basically ofdihydroxyethylene dimethylol urea:

It is widely used in applications to cotton and other cellulosictextiles to impart permanent press qualities. It was used, following themanufacturers recommendation in conjunction with an acid catalyst, ZnNOIt was applied in the form of 10% aqueous solution to which was alsoadded 1% sodium bisulphite.

Samples of a wool fabric were treated with the various agents describedabove, using the following technique in each case. The fabric waswet-out in the aqueous solution or emulsion of the agent, put throughsqueeze rolls to 80-100% wet pick-up, and dried in air overnight. Thenext day the samples were moistened by spraying with water and werecreased by folding and application of steam and pressure. The creasedsamples were then cured in an oven3l0 F. for minutes.

The cured samples were then subjected to three 75- minute washes withtumble drying after each wash. After Example 8 Experiments were carriedout to compare the effectiveness of the process of the invention withone wherein a commercially-employed shrinkproofing treatment wasfollowed by treatment with sodium bisulphite.

A sample of undyed worsted (wool) fabric was given a shrinkproofingtreatment by application of polyhexamethylene sebacamide throughinterfacial polymerization, as disclosed in Pat. 3,078,138. Inparticular, the fabric was first immersed in an aqueous solution ofhexamethylene diamine (1.5%) and sodium carbonate (1.5%), run throughsqueeze rolls, then immersed in a solution of sebacoyl chloride (2.0%)in a volatile petroleum hydrocarbon solvent, run through squeeze rolls,and washed in water to remove unreacted materials, and dried. The fabricwas then wet-out with an aqueous 2% solution of sodium bisulphite andcreased by folding and application of steam and pressure, as describedin Example 2. The treated fabric was then subjected to a -minute wash,as described above, and tumble dried. It was observed that the creasehad disappeared. In contrast, a sample of the same fabric treated asdescribed in Example 2 with a 2% emulsion of the aziridine-modifiedpolyurethane and 1% sodium bisulphite, retained its creases even afterfour 75-minute washes (each followed by tumble drying). This unusualdurability of the creases plainly indicates that our process involves asynergistic effect between the aziridine-modified polyurethane and thebisulphite.

Example 9 A hydroxy-terminated polyethylene adipate of molecular weightapproximately 6500 was end-capped by reaction with an excess of toluenediisocyanate to produce a polyether polyurethane with terminal NCOgroups. One mole of this polymer was then reacted with two moles ofethylene imine to produce an aziridine-terminated polyetherpolyurethane. A 2% emulsion of this aziridine-modified polymer wasprepared as in Example 1, part (B), and wool fabric was treated with theemulsion as described in Example 2. After four 75-minute washes thetreated fabric showed 3% shrinkage in the warp and 2% shrinkage in thefill directions, while the control (untreated wool fabric) had shrunk30% in the warp and 24% in the fill under the same washing conditions.

Having thus described our invention, we claim:

1. A process of treating textile material to improve its propertieswhich comprises depositing on the textile material an aziridine-modifiedpolyurethane of the structure I CHR" wherein:

A is the residue of a polyether polyol or polyester polyol having avalence of n,

R is a hydrocarbon radical containing at least two carbon atoms,

CHR

R" is hydrogen or a lower alkyl radical,

n is an integer from 2 to 10, and

x is an integer from 1 to 2.

2. The process of claim 1 wherein A is the residue of apolyalkyleneether glycol and n is 2.

3. The process of claim 1 wherein is the tolylene radical.

4. The process of claim 1 wherein the textile material is wool.

5. The process of claim 1 wherein a sulphur-containing reductivedisulphide-splitting agent is deposited on the textile material.

6. The process of claim 1 wherein the textile material containing thedeposited aziridine-modified polyurethane is subjected togarment-fabricating operations including cutting, sewing, and pressing,and the fabricated garment is cured to insolubilize theaziridine-modified polyurethane in situ to provide a press-free garmentwherein imparted creases are unaffected by repeated washing of thegarment.

7. The process of claim 6 wherein a sulphur-containing reductivedisulphide-splitting agent is deposited on the textile material prior tocuring.

8. Textile material carrying a deposit of an aziridinemodifiedpolyurethane of the structure wherein:

R is hydrogen, halogen, lower alkoxy, or a radical of the structure CHRR is hydrogen or a lower alkyl radical,

n is an integer from 2 to 10, and

x is an integer from 1 to 2.

9. The product of claim 8 wherein A is the residue of apolyalkyleneether glycol and n is 2.

10. The product of claim 8 wherein R l h is the tolylene radical.

11. The product of claim 8 wherein the textile material is wool.

12. The product of claim 8 wherein said deposit is cured in situ on thetextile material.

13. The product of claim 8 wherein said deposit is cured in situ on thetextile material and in the presence of a sulphur containing reductivedisulphide splitting agent.

14. The product of claim 13 wherein said agent is an alkali metalbisulphite.

References Cited UNITED STATES PATENTS 2,327,760 8/1943 Bestian et al81l6 2,881,046 4/1959 Rose et a1 8-l27.6 2,891,877 6/1959 Chance et al.8-127.6 3,279,882 10/ 1966 Tesoro 8l27.6 3,285,798 11/ 1966 Tesoro 2602X 3,300,274 1/1967 Pittman et al 8-1276 3,454,671 7/1969 Oertel 26077.5X

DONALD LEVY, Primary Examiner C. E. VAN HORN, Assistant Examiner US. Cl.X.R.

